    var event_util = {
      //添加事件
      addHandler: function(element, type, handler) {
          if(element.addEventListener) {                         
              element.addEventListener(type, handler, false);    
          } else if(element.attachEvent) {                       
              element.attachEvent("on" + type, handler);
          } else {
              element["on" + type] = handler;                    
          }
      },
      //移除事件
      removeHandler: function(element, type, handler) {
          if(element.removeEventListener) {
              element.removeEventListener(type, handler, false);
          } else if(element.detachEvent) {
              element.detachEvent("on" + type, handler);
          } else {
              element["on" + type] = null;
          }
      },
      //获取事件对象
      getEvent: function(event) {
          return event ? event : window.event;
      },
      //获取事件目标
      getTarget: function(event) {
          return event.target || event.srcElement;
      },
      //阻止事件冒泡
      stopPropagation: function(event) {
          if(event.stopPropagation) {
              event.stopPropagation();
          } else {
              event.cancelBubble = true;
          }
      },
      //取消事件默认行为
      preventDefault: function(event) {
          if(event.preventDefault) {
              event.preventDefault();
          } else {
              event.returnValue = false;
          }
      },
      //获取相关元素
      getRelatedTarget: function(event) {
          if(event.relatedTarget) {
              return event.relatedTarget;
          } else if(event.fromElement) {
              return event.fromElement;
          } else if(event.toElement) {
              return event.toElement;
          } else {
              return null;
          }
      }
  }
  